1. Field of Invention
This invention relates to a method and apparatus for stretching dough, and, more particularly, to a method and apparatus for stretching plastic materials for bread dough or confectionery dough.
2. Description of Prior Art
Plastic materials for bread dough or confectionery dough have been continuously stretched by various stretchers. Previously an apparatus for stretching dough in which two conveyors are serially disposed and a roller is disposed at a fixed position above a downstream conveyor has been preferably used due to its relatively simple mechanism. In this prior apparatus the downstream conveyor is driven faster than the upstream one so that the dough is stretched. The roller is rotated at the same peripheral speed as that of the conveying speed of the downstream conveyor, and in the same direction as that of the dough being conveyed. The main function of this prior apparatus depends on the compression by the roller of the dough, while the roller is in contact with the surface of the dough, and rolls on it. Therefore, the stretching ratio of the dough in terms of the thickness of the dough before stretching is small compared to the thickness of the dough after stretching, and the tissue of the dough tends to be destroyed. Further, when the thickness of the dough to be stretched is relatively larger compared to the gap between the roller and the surface of the downstream conveyor, frequently the dough cannot smoothly advance between the roller and the surface of the conveyor, and a substantial part of it stays in front of the roller, which results in lowering the manufacturing efficiency.